Accenture has insisted that it can avoid any conflict of interest and "would not provide auditing and programmatic services to the same client".

Accenture’s critics have suggested it could dispose of its media audit business and the consulting giant did not rule that out when asked by Campaign.

Accenture Interactive has done work in performance marketing for around five years and began talking about setting up in-house programmatic trading desks for clients last year.

Alan Rutherford, chairman of Ebiquity’s media practice, which carries out media audits for dozens of leading advertisers, described Accenture’s launch of a programmatic buying unit this week as "a game-changer" and "a clear conflict" because of the consulting giant’s "legacy media auditing services".

Rutherford said ad agency groups will be "unhappy" at the prospect of Accenture Interactive moving into media-buying when a sister business has "access to confidential client and agency media data and financial information".

Stephen Broderick, chief executive of FirmDecisions, which checks that agencies have complied with contracts, said: "This is a conflict. The role of an auditor must be entirely independent and its decisions free from financial gain.

"This move allows Accenture to effectively mark its own homework. No client or agency group would be happy with this practice."

Graham Brown, co-founder of MediaSense, which manages pitches for advertisers such as Adidas and Ocado, said he welcomed the launch of Accenture’s programmatic unit as it could be a "credible offering in the marketplace" that could benefit clients.

However, he warned: "If it is the case that Accenture want to be a solutions provider, they can’t also be marking competitors’ homework. There is a fundamental conflict that they need to address.

"The logical conclusion is they are going to have to move completely out of the business of presenting themselves as impartial advisers on media planning and buying services and commenting on agencies’ capabilties because they have a vested interest.

"Chinese walls won’t suffice at a time when the whole industry is rightly concerned about conflicts of interests."

Tom Denford, co-founder and chief strategy officer of ID Comms, which has runs pitches for Sky, HSBC and IKEA, said: "It’s definitely a conflict of interest. If potentially Accenture are advising on media activity and then responsible for setting the performance of that media activity, that would be marking your own homework and that wouldn’t be tolerated by marketers, I think.

"Accenture don’t run many pitches these days but, of course, it would be [a conflict] if they ran a pitch.

"The revenues from programmatic consulting and eventually programmatic buying will soon vastly outweigh the revenue and profit on the media audit business, so they will be forced to dispose of it."

Adrian Jenkins, director of Financial Progression, a chartered accountancy firm that specialises in media contract compliance, said Accenture’s move into programmatic planning and buying would raise questions, although he stopped short of suggesting it was a conflict.

"The fundamental principles of auditor independence centre around objectivity and integrity," Jenkins said. "Before taking on a piece of work, an auditor must consider whether it involves threats to those fundamental principles - for example, by self-interest, self-review, being in an advocacy position, overfamiliarity or intimidation."

Jenkins went on: "Where actual and perceived threats to auditor independence exist, safeguards must be put in place to eliminate them or reduce them to insignificant levels.

"With its move into programmatic media buying, clients and agencies will be seeking evidence from Accenture's media performance and compliance audit practices that appropriate safeguards are in place."

MediaCom's Allan wrote on LinkedIn: "Accenture and the other auditors cannot audit and provide media execution as well.

"They can’t police transparency and measure performance for clients while also competing with those of us who provide media services."

He added: "If it [Accenture] wants to continue to be an auditor then its new business is frankly incompatible with that role."

Another global agency leader said privately: "It’s absolutely a conflict because Accenture sees all the media pricing. It’s outrageous. If I was a client, I’d very nervous.

"However, I’m not sure if any agency will refuse an Accenture media audit at this stage because it’s such an established practice and you have to be quite ballsy to turn down pitches.

"Media agencies need their own trade body to deal with issues like this."

Scott Tieman, global lead of programmatic services at Accenture Interactive, maintained the consulting giant is able to manage any conflict.

He said: "Media audits are conducted by a dedicated team within the procurement division within Accenture Operations and confidential data and non-disclosure protections, firewalls and policies are in place to ensure that information is not shared across other parts of the Accenture business."

He added: "We would not provide auditing and programmatic services to the same client."

Asked by Campaign if Accenture could resolve a perception of conflict by exiting the Media Management business, Tieman said: "We are constantly evolving our business to adapt to changing industry and client demands."

Accenture Interactive has been moving rapidly onto agencies’ turf in the last 18 months, making more than a dozen acquisitions.

The share prices of WPP, Omnicom and Interpublic fell on Wednesday following the news of the launch of the Programmatic Services unit.

Accenture Interactive claims its approach to programmatic will be transparent and will not rely on media arbitrage to generate profit.

Agency executives questioned whether it would be easy for new entrants to become involved in media-buying if they have only a narrow area of expertise such as programmatic.

Sarah Warner, digital investment lead for programmatic and video at Group M, the media-buying arm of WPP, said: "It is a very complex media eco-system and we feel very well-suited to continue to serve our clients. It’s not just about the execution of programmatic campaigns and having expertise in certain pockets.

"It’s about understanding the entire eco-system and all the players out there and making sure we invest in the best way for our clients and policing the supply chain."